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-rw-r--r--read-cache.c331
1 files changed, 263 insertions, 68 deletions
diff --git a/read-cache.c b/read-cache.c
index 6c8f395836..79e3bbe024 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -12,9 +12,15 @@
#include "commit.h"
#include "blob.h"
#include "resolve-undo.h"
+#include "strbuf.h"
+#include "varint.h"
static struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really);
+/* Mask for the name length in ce_flags in the on-disk index */
+
+#define CE_NAMEMASK (0x0fff)
+
/* Index extensions.
*
* The first letter should be 'A'..'Z' for extensions that are not
@@ -52,8 +58,8 @@ void rename_index_entry_at(struct index_state *istate, int nr, const char *new_n
new = xmalloc(cache_entry_size(namelen));
copy_cache_entry(new, old);
- new->ce_flags &= ~(CE_STATE_MASK | CE_NAMEMASK);
- new->ce_flags |= (namelen >= CE_NAMEMASK ? CE_NAMEMASK : namelen);
+ new->ce_flags &= ~CE_STATE_MASK;
+ new->ce_namelen = namelen;
memcpy(new->name, new_name, namelen + 1);
cache_tree_invalidate_path(istate->cache_tree, old->name);
@@ -393,10 +399,8 @@ int df_name_compare(const char *name1, int len1, int mode1,
return c1 - c2;
}
-int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
+int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2)
{
- int len1 = flags1 & CE_NAMEMASK;
- int len2 = flags2 & CE_NAMEMASK;
int len = len1 < len2 ? len1 : len2;
int cmp;
@@ -408,18 +412,19 @@ int cache_name_compare(const char *name1, int flags1, const char *name2, int fla
if (len1 > len2)
return 1;
- /* Compare stages */
- flags1 &= CE_STAGEMASK;
- flags2 &= CE_STAGEMASK;
-
- if (flags1 < flags2)
+ if (stage1 < stage2)
return -1;
- if (flags1 > flags2)
+ if (stage1 > stage2)
return 1;
return 0;
}
-int index_name_pos(const struct index_state *istate, const char *name, int namelen)
+int cache_name_compare(const char *name1, int len1, const char *name2, int len2)
+{
+ return cache_name_stage_compare(name1, len1, 0, name2, len2, 0);
+}
+
+int index_name_stage_pos(const struct index_state *istate, const char *name, int namelen, int stage)
{
int first, last;
@@ -428,7 +433,7 @@ int index_name_pos(const struct index_state *istate, const char *name, int namel
while (last > first) {
int next = (last + first) >> 1;
struct cache_entry *ce = istate->cache[next];
- int cmp = cache_name_compare(name, namelen, ce->name, ce->ce_flags);
+ int cmp = cache_name_stage_compare(name, namelen, stage, ce->name, ce_namelen(ce), ce_stage(ce));
if (!cmp)
return next;
if (cmp < 0) {
@@ -440,6 +445,11 @@ int index_name_pos(const struct index_state *istate, const char *name, int namel
return -first-1;
}
+int index_name_pos(const struct index_state *istate, const char *name, int namelen)
+{
+ return index_name_stage_pos(istate, name, namelen, 0);
+}
+
/* Remove entry, return true if there are more entries to go.. */
int remove_index_entry_at(struct index_state *istate, int pos)
{
@@ -579,7 +589,7 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
size = cache_entry_size(namelen);
ce = xcalloc(1, size);
memcpy(ce->name, path, namelen);
- ce->ce_flags = namelen;
+ ce->ce_namelen = namelen;
if (!intent_only)
fill_stat_cache_info(ce, st);
else
@@ -681,7 +691,8 @@ struct cache_entry *make_cache_entry(unsigned int mode,
hashcpy(ce->sha1, sha1);
memcpy(ce->name, path, len);
- ce->ce_flags = create_ce_flags(len, stage);
+ ce->ce_flags = create_ce_flags(stage);
+ ce->ce_namelen = len;
ce->ce_mode = create_ce_mode(mode);
if (refresh)
@@ -818,7 +829,7 @@ static int has_dir_name(struct index_state *istate,
}
len = slash - name;
- pos = index_name_pos(istate, name, create_ce_flags(len, stage));
+ pos = index_name_stage_pos(istate, name, len, stage);
if (pos >= 0) {
/*
* Found one, but not so fast. This could
@@ -908,7 +919,7 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
int new_only = option & ADD_CACHE_NEW_ONLY;
cache_tree_invalidate_path(istate->cache_tree, ce->name);
- pos = index_name_pos(istate, ce->name, ce->ce_flags);
+ pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
/* existing match? Just replace it. */
if (pos >= 0) {
@@ -940,7 +951,7 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
if (!ok_to_replace)
return error("'%s' appears as both a file and as a directory",
ce->name);
- pos = index_name_pos(istate, ce->name, ce->ce_flags);
+ pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce));
pos = -pos-1;
}
return pos + 1;
@@ -1117,7 +1128,7 @@ int refresh_index(struct index_state *istate, unsigned int flags, const char **p
continue;
if (pathspec &&
- !match_pathspec(pathspec, ce->name, strlen(ce->name), 0, seen))
+ !match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, seen))
filtered = 1;
if (ce_stage(ce)) {
@@ -1179,15 +1190,74 @@ static struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int reall
return refresh_cache_ent(&the_index, ce, really, NULL, NULL);
}
+
+/*****************************************************************
+ * Index File I/O
+ *****************************************************************/
+
+#define INDEX_FORMAT_DEFAULT 3
+
+/*
+ * dev/ino/uid/gid/size are also just tracked to the low 32 bits
+ * Again - this is just a (very strong in practice) heuristic that
+ * the inode hasn't changed.
+ *
+ * We save the fields in big-endian order to allow using the
+ * index file over NFS transparently.
+ */
+struct ondisk_cache_entry {
+ struct cache_time ctime;
+ struct cache_time mtime;
+ unsigned int dev;
+ unsigned int ino;
+ unsigned int mode;
+ unsigned int uid;
+ unsigned int gid;
+ unsigned int size;
+ unsigned char sha1[20];
+ unsigned short flags;
+ char name[FLEX_ARRAY]; /* more */
+};
+
+/*
+ * This struct is used when CE_EXTENDED bit is 1
+ * The struct must match ondisk_cache_entry exactly from
+ * ctime till flags
+ */
+struct ondisk_cache_entry_extended {
+ struct cache_time ctime;
+ struct cache_time mtime;
+ unsigned int dev;
+ unsigned int ino;
+ unsigned int mode;
+ unsigned int uid;
+ unsigned int gid;
+ unsigned int size;
+ unsigned char sha1[20];
+ unsigned short flags;
+ unsigned short flags2;
+ char name[FLEX_ARRAY]; /* more */
+};
+
+/* These are only used for v3 or lower */
+#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,name) + (len) + 8) & ~7)
+#define ondisk_cache_entry_size(len) align_flex_name(ondisk_cache_entry,len)
+#define ondisk_cache_entry_extended_size(len) align_flex_name(ondisk_cache_entry_extended,len)
+#define ondisk_ce_size(ce) (((ce)->ce_flags & CE_EXTENDED) ? \
+ ondisk_cache_entry_extended_size(ce_namelen(ce)) : \
+ ondisk_cache_entry_size(ce_namelen(ce)))
+
static int verify_hdr(struct cache_header *hdr, unsigned long size)
{
git_SHA_CTX c;
unsigned char sha1[20];
+ int hdr_version;
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
return error("bad signature");
- if (hdr->hdr_version != htonl(2) && hdr->hdr_version != htonl(3))
- return error("bad index version");
+ hdr_version = ntohl(hdr->hdr_version);
+ if (hdr_version < 2 || 4 < hdr_version)
+ return error("bad index version %d", hdr_version);
git_SHA1_Init(&c);
git_SHA1_Update(&c, hdr, size - 20);
git_SHA1_Final(sha1, &c);
@@ -1221,7 +1291,75 @@ int read_index(struct index_state *istate)
return read_index_from(istate, get_index_file());
}
-static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk)
+#ifndef NEEDS_ALIGNED_ACCESS
+#define ntoh_s(var) ntohs(var)
+#define ntoh_l(var) ntohl(var)
+#else
+static inline uint16_t ntoh_s_force_align(void *p)
+{
+ uint16_t x;
+ memcpy(&x, p, sizeof(x));
+ return ntohs(x);
+}
+static inline uint32_t ntoh_l_force_align(void *p)
+{
+ uint32_t x;
+ memcpy(&x, p, sizeof(x));
+ return ntohl(x);
+}
+#define ntoh_s(var) ntoh_s_force_align(&(var))
+#define ntoh_l(var) ntoh_l_force_align(&(var))
+#endif
+
+static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *ondisk,
+ unsigned int flags,
+ const char *name,
+ size_t len)
+{
+ struct cache_entry *ce = xmalloc(cache_entry_size(len));
+
+ ce->ce_ctime.sec = ntoh_l(ondisk->ctime.sec);
+ ce->ce_mtime.sec = ntoh_l(ondisk->mtime.sec);
+ ce->ce_ctime.nsec = ntoh_l(ondisk->ctime.nsec);
+ ce->ce_mtime.nsec = ntoh_l(ondisk->mtime.nsec);
+ ce->ce_dev = ntoh_l(ondisk->dev);
+ ce->ce_ino = ntoh_l(ondisk->ino);
+ ce->ce_mode = ntoh_l(ondisk->mode);
+ ce->ce_uid = ntoh_l(ondisk->uid);
+ ce->ce_gid = ntoh_l(ondisk->gid);
+ ce->ce_size = ntoh_l(ondisk->size);
+ ce->ce_flags = flags & ~CE_NAMEMASK;
+ ce->ce_namelen = len;
+ hashcpy(ce->sha1, ondisk->sha1);
+ memcpy(ce->name, name, len);
+ ce->name[len] = '\0';
+ return ce;
+}
+
+/*
+ * Adjacent cache entries tend to share the leading paths, so it makes
+ * sense to only store the differences in later entries. In the v4
+ * on-disk format of the index, each on-disk cache entry stores the
+ * number of bytes to be stripped from the end of the previous name,
+ * and the bytes to append to the result, to come up with its name.
+ */
+static unsigned long expand_name_field(struct strbuf *name, const char *cp_)
+{
+ const unsigned char *ep, *cp = (const unsigned char *)cp_;
+ size_t len = decode_varint(&cp);
+
+ if (name->len < len)
+ die("malformed name field in the index");
+ strbuf_remove(name, name->len - len, len);
+ for (ep = cp; *ep; ep++)
+ ; /* find the end */
+ strbuf_add(name, cp, ep - cp);
+ return (const char *)ep + 1 - cp_;
+}
+
+static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
+ unsigned long *ent_size,
+ struct strbuf *previous_name)
{
struct cache_entry *ce;
size_t len;
@@ -1229,14 +1367,14 @@ static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk)
unsigned int flags;
/* On-disk flags are just 16 bits */
- flags = ntohs(ondisk->flags);
+ flags = ntoh_s(ondisk->flags);
len = flags & CE_NAMEMASK;
if (flags & CE_EXTENDED) {
struct ondisk_cache_entry_extended *ondisk2;
int extended_flags;
ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
- extended_flags = ntohs(ondisk2->flags2) << 16;
+ extended_flags = ntoh_s(ondisk2->flags2) << 16;
/* We do not yet understand any bit out of CE_EXTENDED_FLAGS */
if (extended_flags & ~CE_EXTENDED_FLAGS)
die("Unknown index entry format %08x", extended_flags);
@@ -1246,27 +1384,22 @@ static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk)
else
name = ondisk->name;
- if (len == CE_NAMEMASK)
- len = strlen(name);
-
- ce = xmalloc(cache_entry_size(len));
-
- ce->ce_ctime.sec = ntohl(ondisk->ctime.sec);
- ce->ce_mtime.sec = ntohl(ondisk->mtime.sec);
- ce->ce_ctime.nsec = ntohl(ondisk->ctime.nsec);
- ce->ce_mtime.nsec = ntohl(ondisk->mtime.nsec);
- ce->ce_dev = ntohl(ondisk->dev);
- ce->ce_ino = ntohl(ondisk->ino);
- ce->ce_mode = ntohl(ondisk->mode);
- ce->ce_uid = ntohl(ondisk->uid);
- ce->ce_gid = ntohl(ondisk->gid);
- ce->ce_size = ntohl(ondisk->size);
- ce->ce_flags = flags;
-
- hashcpy(ce->sha1, ondisk->sha1);
-
- memcpy(ce->name, name, len);
- ce->name[len] = '\0';
+ if (!previous_name) {
+ /* v3 and earlier */
+ if (len == CE_NAMEMASK)
+ len = strlen(name);
+ ce = cache_entry_from_ondisk(ondisk, flags, name, len);
+
+ *ent_size = ondisk_ce_size(ce);
+ } else {
+ unsigned long consumed;
+ consumed = expand_name_field(previous_name, name);
+ ce = cache_entry_from_ondisk(ondisk, flags,
+ previous_name->buf,
+ previous_name->len);
+
+ *ent_size = (name - ((char *)ondisk)) + consumed;
+ }
return ce;
}
@@ -1279,12 +1412,11 @@ int read_index_from(struct index_state *istate, const char *path)
struct cache_header *hdr;
void *mmap;
size_t mmap_size;
+ struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
- errno = EBUSY;
if (istate->initialized)
return istate->cache_nr;
- errno = ENOENT;
istate->timestamp.sec = 0;
istate->timestamp.nsec = 0;
fd = open(path, O_RDONLY);
@@ -1297,36 +1429,43 @@ int read_index_from(struct index_state *istate, const char *path)
if (fstat(fd, &st))
die_errno("cannot stat the open index");
- errno = EINVAL;
mmap_size = xsize_t(st.st_size);
if (mmap_size < sizeof(struct cache_header) + 20)
die("index file smaller than expected");
mmap = xmmap(NULL, mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
- close(fd);
if (mmap == MAP_FAILED)
die_errno("unable to map index file");
+ close(fd);
hdr = mmap;
if (verify_hdr(hdr, mmap_size) < 0)
goto unmap;
+ istate->version = ntohl(hdr->hdr_version);
istate->cache_nr = ntohl(hdr->hdr_entries);
istate->cache_alloc = alloc_nr(istate->cache_nr);
istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
istate->initialized = 1;
+ if (istate->version == 4)
+ previous_name = &previous_name_buf;
+ else
+ previous_name = NULL;
+
src_offset = sizeof(*hdr);
for (i = 0; i < istate->cache_nr; i++) {
struct ondisk_cache_entry *disk_ce;
struct cache_entry *ce;
+ unsigned long consumed;
disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
- ce = create_from_disk(disk_ce);
+ ce = create_from_disk(disk_ce, &consumed, previous_name);
set_index_entry(istate, i, ce);
- src_offset += ondisk_ce_size(ce);
+ src_offset += consumed;
}
+ strbuf_release(&previous_name_buf);
istate->timestamp.sec = st.st_mtime;
istate->timestamp.nsec = ST_MTIME_NSEC(st);
@@ -1353,7 +1492,6 @@ int read_index_from(struct index_state *istate, const char *path)
unmap:
munmap(mmap, mmap_size);
- errno = EINVAL;
die("index file corrupt");
}
@@ -1510,12 +1648,11 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
}
}
-static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
+/* Copy miscellaneous fields but not the name */
+static char *copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk,
+ struct cache_entry *ce)
{
- int size = ondisk_ce_size(ce);
- struct ondisk_cache_entry *ondisk = xcalloc(1, size);
- char *name;
- int result;
+ short flags;
ondisk->ctime.sec = htonl(ce->ce_ctime.sec);
ondisk->mtime.sec = htonl(ce->ce_mtime.sec);
@@ -1528,16 +1665,60 @@ static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce)
ondisk->gid = htonl(ce->ce_gid);
ondisk->size = htonl(ce->ce_size);
hashcpy(ondisk->sha1, ce->sha1);
- ondisk->flags = htons(ce->ce_flags);
+
+ flags = ce->ce_flags;
+ flags |= (ce_namelen(ce) >= CE_NAMEMASK ? CE_NAMEMASK : ce_namelen(ce));
+ ondisk->flags = htons(flags);
if (ce->ce_flags & CE_EXTENDED) {
struct ondisk_cache_entry_extended *ondisk2;
ondisk2 = (struct ondisk_cache_entry_extended *)ondisk;
ondisk2->flags2 = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16);
- name = ondisk2->name;
+ return ondisk2->name;
+ }
+ else {
+ return ondisk->name;
+ }
+}
+
+static int ce_write_entry(git_SHA_CTX *c, int fd, struct cache_entry *ce,
+ struct strbuf *previous_name)
+{
+ int size;
+ struct ondisk_cache_entry *ondisk;
+ char *name;
+ int result;
+
+ if (!previous_name) {
+ size = ondisk_ce_size(ce);
+ ondisk = xcalloc(1, size);
+ name = copy_cache_entry_to_ondisk(ondisk, ce);
+ memcpy(name, ce->name, ce_namelen(ce));
+ } else {
+ int common, to_remove, prefix_size;
+ unsigned char to_remove_vi[16];
+ for (common = 0;
+ (ce->name[common] &&
+ common < previous_name->len &&
+ ce->name[common] == previous_name->buf[common]);
+ common++)
+ ; /* still matching */
+ to_remove = previous_name->len - common;
+ prefix_size = encode_varint(to_remove, to_remove_vi);
+
+ if (ce->ce_flags & CE_EXTENDED)
+ size = offsetof(struct ondisk_cache_entry_extended, name);
+ else
+ size = offsetof(struct ondisk_cache_entry, name);
+ size += prefix_size + (ce_namelen(ce) - common + 1);
+
+ ondisk = xcalloc(1, size);
+ name = copy_cache_entry_to_ondisk(ondisk, ce);
+ memcpy(name, to_remove_vi, prefix_size);
+ memcpy(name + prefix_size, ce->name + common, ce_namelen(ce) - common);
+
+ strbuf_splice(previous_name, common, to_remove,
+ ce->name + common, ce_namelen(ce) - common);
}
- else
- name = ondisk->name;
- memcpy(name, ce->name, ce_namelen(ce));
result = ce_write(c, fd, ondisk, size);
free(ondisk);
@@ -1573,10 +1754,11 @@ int write_index(struct index_state *istate, int newfd)
{
git_SHA_CTX c;
struct cache_header hdr;
- int i, err, removed, extended;
+ int i, err, removed, extended, hdr_version;
struct cache_entry **cache = istate->cache;
int entries = istate->cache_nr;
struct stat st;
+ struct strbuf previous_name_buf = STRBUF_INIT, *previous_name;
for (i = removed = extended = 0; i < entries; i++) {
if (cache[i]->ce_flags & CE_REMOVE)
@@ -1590,24 +1772,36 @@ int write_index(struct index_state *istate, int newfd)
}
}
+ if (!istate->version)
+ istate->version = INDEX_FORMAT_DEFAULT;
+
+ /* demote version 3 to version 2 when the latter suffices */
+ if (istate->version == 3 || istate->version == 2)
+ istate->version = extended ? 3 : 2;
+
+ hdr_version = istate->version;
+
hdr.hdr_signature = htonl(CACHE_SIGNATURE);
- /* for extended format, increase version so older git won't try to read it */
- hdr.hdr_version = htonl(extended ? 3 : 2);
+ hdr.hdr_version = htonl(hdr_version);
hdr.hdr_entries = htonl(entries - removed);
git_SHA1_Init(&c);
if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
return -1;
+ previous_name = (hdr_version == 4) ? &previous_name_buf : NULL;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
if (ce->ce_flags & CE_REMOVE)
continue;
if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce))
ce_smudge_racily_clean_entry(ce);
- if (ce_write_entry(&c, newfd, ce) < 0)
+ if (is_null_sha1(ce->sha1))
+ return error("cache entry has null sha1: %s", ce->name);
+ if (ce_write_entry(&c, newfd, ce, previous_name) < 0)
return -1;
}
+ strbuf_release(&previous_name_buf);
/* Write extension data here */
if (istate->cache_tree) {
@@ -1660,11 +1854,12 @@ int read_index_unmerged(struct index_state *istate)
if (!ce_stage(ce))
continue;
unmerged = 1;
- len = strlen(ce->name);
+ len = ce_namelen(ce);
size = cache_entry_size(len);
new_ce = xcalloc(1, size);
memcpy(new_ce->name, ce->name, len);
- new_ce->ce_flags = create_ce_flags(len, 0) | CE_CONFLICTED;
+ new_ce->ce_flags = create_ce_flags(0) | CE_CONFLICTED;
+ new_ce->ce_namelen = len;
new_ce->ce_mode = ce->ce_mode;
if (add_index_entry(istate, new_ce, 0))
return error("%s: cannot drop to stage #0",
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 09:35:43 +0000